Lynette White was murdered in Cardiff on Valentine’s Day 1988. Photograph: PA

More than 100 serving and retired police officers came under scrutiny during a criminal investigation into one of the most notorious miscarriages of justice, a report reveals.

Twenty officers were arrested and 13 charged over alleged corruption that led to the wrongful jailing of the Cardiff Three for the brutal murder of Lynette White.

The report, published on Monday, spells out the huge scale of the eight-year criminal inquiry, the key factor blamed for the eventual collapse of the corruption case two years ago. It says a total of 121 current or former officers were categorised as persons of interest.

On top of the arrests, six were interviewed under caution and 29 interviewed as possible witnesses. A further seven were designated as witnesses but refused to co-operate. No action was taken with regard to the 59 others.

The report adds that more than 800,000 pages of material were generated and 5,000 exhibits gathered.

White, 20, a sex worker, was murdered in a tiny flat in the dockland area of Cardiff on Valentine's Day 1988. Five men were put on trial for her murder and three – Yusef Abdullahi, Stephen Miller and Tony Paris – were jailed. Two years later, in 1992, they were freed by the court of appeal.

In 2003 another man, Jeffrey Gafoor, who had no connection with the three, admitted he was the killer, and South Wales police launched a criminal inquiry into the way some of its own officers had acted. In December 2011, the trial of the first eight who had been charged collapsed when it emerged that files of documents had not been disclosed to the defence and could not be found.

Proceedings against all 13 were abandoned and there was an outcry over the failure of an investigation and trial that had cost an estimated £30m.

This year, reports from the Independent Police Complaints Commission and HM Crown Prosecution Inspectorate said the police and prosecution had failed to control the reams of material in the case.

The new report by South Wales police gives an insight into the size of the task. It says: "The extent of the material involved in this inquiry was the single biggest challenge that it faced. A vast amount of material was analysed and assessed."

The IPCC said the Welsh force's investigation of itself over the case had been carried out with integrity and diligence and had restored its public reputation.

Tom Davies, the IPCC commissioner for Wales, said: "This was a groundbreaking investigation and many lessons have been learnt from this to guide future historical crime and serious misconduct investigations and improve police practice in future."

The report flags up a very clear photofit of a white man who was seen leaving the scene of the murder.

The report says: "This man was never eliminated and yet several months later the investigation team were to arrest and charge a group of five black men; eventually three were convicted."

The report quotes examples of how witnesses were allegedly treated. One claimed: "They were playing good cop, bad cop type of thing. I was in a room, one of them would come in and be really nice and offer me cigarettes and a cup of tea and then the other one would come in and start shouting and bawling and throwing furniture around the room."

Another, a woman, claimed officers said harm would come to her children if she did not co-operate. She said: "The police threatened me that my son would end up in care and that I would be charged with the murder of Lynette White. I was shown photographs of children with injuries. I was told that this would happen to my son … I was very scared."